Immediate Effects of Focal Muscle Vibration on Squat Power and Velocity in Amateur Athletes: A Randomized Controlled Trial

Background: Squat exercises are widely recognized for their ability to improve sports performance. Recent advancements in force/velocity profiling have highlighted the importance of power and velocity in explosive movements. While various training methods have been applied to enhance these parameters, their effectiveness remains inconsistent. Focal vibration has emerged as a potential intervention, yet its impact on squat performance has not been extensively explored. The aim was to evaluate the effectiveness of focal vibration with voluntary contractions on power/velocity during a squat exercise in amateur athletes in comparison with voluntary contraction in isolation. Methods: A double-blind, randomized clinical trial with 72 amateur athletes. Velocity, power, muscle activity, perceived effort, and clinical change were measured. The experimental group received focal muscle vibration therapy (100-180 Hz) combined with voluntary contraction, while the sham group underwent identical procedures and focal muscle vibration without the vibrating head, close to the muscle belly but without touching the skin. Results: Statistically significant improvements in the experimental group were found for mean power (p < 0.001; ES = 0.08), peak velocity (p < 0.010; ES = 0.42), and mean velocity (p < 0.001; ES = 0.66) during the squat. Between-group analysis favored the experimental group in peak power (p < 0.049; ES = 0.65), mean power (p < 0.034; ES = 1.42), peak velocity (p < 0.024; ES = 0.095), and mean velocity (p < 0.002; ES = 1.67). Conclusions: Focal muscle vibration (100-180 Hz) combined with active muscle contraction significantly enhances power and velocity during squat exercises in amateur athletes.